1. Field of the Invention
The present invention generally relates to the distribution of required voltage levels to integrated circuit chip modules and, more particularly, to a structure for making such distribution under conditions of high current demand.
2. Description of the Prior Art
Power bus techniques are known for supplying operating voltages to a multiplicity of devices mounted on a common carrier or module to avoid the need for a maze of individual voltage supply wire connections to each of the devices.
For example, U.S. Pat. No. 3,072,874, issued Jan. 8, 1963 to E. L. Roney for Chassis Construction shows a plurality of sheet-like conductors separated by insulator sheets stacked and secured to the underside of a multi-vacuum tube chassis. One end of the sheet conductors are connected to external power supplies. The sheet conductors function as planar bus bars and provide common electrical connections for the vacuum tube sockets terminals. Those tube socket terminals requiring a given voltage supply input are directly connected to an appropriate one of the underlying stacked sheets via vertical openings through the intervening stacked sheets. Connection is made by spring contacts or prongs extending downwardly from the tube socket. The prongs mate with tabs which protrude into the opening and are fixed to the appropriate sheet. Although the technique avoids the disadvantages of a maze of separate wire conductors interconnecting the several stages of a multi-tube equipment to common power supplies, no provision is made for accommodating large currents and the resulting heat-induced expansion mismatches between the chassis and the power busses.
In another application involving a circuit breadboard, a similar insulated multilayer power bus structure is provided underneath the breadboard for supplying circuit operating voltages, as shown in the IBM Technical Disclosure Bulletin article "Bus for Breadboards", by M. A. Schappert, Vol. 24, No. 9, February 1982, pages 4488-4489. The different layers of the power bus structure are connected to the required terminals of the breadboard by insulated conducting pins of appropriate length that extend downwardly through holes in the structure and make spring pressure contact with respective layers. Again, however, no provision is made for high current or for the resulting thermal expansion mismatch between breadboard and power bus structure.